Study On Degradable Mulch Sheet Made With Bagasse

Mulch sheet has been introduced in China since the late seventies and developed rapidly. By covering mulch sheet, the temperature and moisture of soil can be preserved, loss of water and nurishment can be decreased, which lead to yield raise. However, the plastic mulch sheet is used widely in China at present, it can t be degradated biologically, which cause critical pollution to the soil due to its high stability. In recent years, many kinds of degradable mulch sheet are being researched.The paper studied preparation techonology of bagasse pulp and mulch sheet. The aim of the former is to determine the best prehydrolysis condition; The emphasis of the later is to determine the best condition of viscose and mulch sheet preparation, and studied the major factors and chemical changes in various processes.The results showed, the best prehydrolysis conditions is: 1:4 liquor, 130 C temperature, 60mm heat improvement time, 90mm heat4preservation time, 0.06% HC1; The best condition of viscose preparationis :45% NaOH, 35% CS2,l:12 ~ 1:13 liquor, 0.06----0.O8MPa pressure; The best condition of mulch sheet preparation is:180g11 H2S04, 10% NaOH, 8% glycerin.Moreover, the paper also discussed the degradation mechanism of mulch sheet, cellulose dissolving and regeneration mechanism and plastifing mechanism.The study of mulch sheet degradation showed that the surface and internal structure of mulch sheet were ruined gradually. At last, the mulch sheet turned into small pieces ad vanished in soil.This kind of mulch sheet shows good dry tension strength, wet tension strength, as well as transparency and suitable biodegradation, which adapt to environment protection.